Re: Word permutations - frustrated by lists.

*To*: mathgroup at smc.vnet.net*Subject*: [mg71713] Re: Word permutations - frustrated by lists.*From*: dh <dh at metrohm.ch>*Date*: Mon, 27 Nov 2006 04:04:35 -0500 (EST)*References*: <ekbrks$jga$1@smc.vnet.net>

Hi, the easy way to get permutations is: << DiscreteMath`Combinatorica` Permutations[{"d", "e", "a", "r"}] Daniel wooks wrote: > Hello. Am relatively new with Mathematica. > > I seem to have a general problem with results that look right but for > embedded lists. Here is an example of my problem. This is supposed to > be a algorithm to generate all permutations of a string. T > > Clear[arrangements] > arrangements[str_String /; StringLength[str] == 1] := {str}; > arrangements[str_String] := (Prepend[arrangements[StringJoin[ > Rest[#]]]], First[#]) & /@ > NestList[RotateRight, Characters[str], StringLength[str] - 1]; > arrangements["dear"] > > PS This is not homework. I'm rewriting some examples from another > programming book as as practice for Mathematica. >